Mixing capsule

ABSTRACT

A mixing capsule, especially for the production of dental materials, comprises a cartridge that is closed on one end by a piston. The piston has a hemispherical recess that forms a secondary chamber and is closed off from the main chamber of the cartridge by a separating device. A body that is provided in the initial state in the main chamber is used to facilitate the mixing process and to penetrate the separating device at the beginning of the process, whereby the main chamber and the secondary chamber form a single mixing area. The body preferably disintegrates during the mixing process.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a mixing capsule and a devicecontaining a mixing capsule, particularly a mixing device and/or anapplication device, as well as a method for using the mixing capsule,particularly for the preparation of a dental material preferablycontaining several components.

For the production of mixtures of two or more components, mixingcapsules are used, which are filled by the manufacturer with thecomponents in separate chambers. The user combines and mixes thecomponents, for example by destroying a wall separating the chamber.

In the dental area, mixing capsules are known for the production ofdental materials that are frequently mixed from a powdery and a liquidcomponent, wherein the mixing process generally takes place in a shaker.The finished mixed substance is then applied directly to the workingarea, for example a tooth cavity, through an ejection sleeve that ismolded to the mixing capsule.

From DE 36 35 574 A we know of a mixing capsule, which is used for theproduction of joining and sealing masses. In an embodiment described inthis document, a secondary chamber that is incorporated in the ejectorpiston is limited on the side facing the main chamber of the capsule bya foil and on the opposite side by an auxiliary piston that is arrangeddisplaceably in the ejector piston. In the starting position of themixing capsule, a mixing body is provided in the secondary chamber apartfrom the second component, wherein this body initially serves to destroythe foil through manual shifting of the auxiliary piston andsubsequently supports the mixing process. In order to enable the volumereduction necessary for shifting the inner piston including the ball, agas cushion is provided in the mixing chamber.

In another embodiment of a known familiar mixing capsule, the mixingball is initially located in the main chamber. In this case, thesecondary chamber existing in the piston is closed off towards the mainchamber by a cover and on its rear by a bellows. Through manual pressureon the bellows, the cover is pushed away from the piston so that the twochambers connect and activate the capsule.

In both cases, a step that needs to be performed on its own manually isrequired to activate the capsule. Furthermore a gas cushion is requiredin order to enable the volume reduction necessary to loosen the cover.

In a multiple component mixing capsule for dental purposes known from DE94 00 374 U1, a first component is contained in a mixing chamber and asecond, liquid component in a foil bag, which is arranged in a secondarychamber that is separated from the mixing chamber by a sliding wallelement. A cylindrical mixing body contained in the mixing chamberserves the purpose of sliding the wall element at the beginning of themixing process and thus pressing the foil bag together, causing it toburst open and thus releasing the liquid component through a passage forthe fluid incorporated in the wall element.

The difficulty with this device is that the wall element, the foil bagand the capsule itself need to be designed in such a way and dimensionedwith such tolerance settings that the wall element is held in itsoriginal position during storage and transport position of the capsule.But it is shifted under the influence of the mixing body so far and withsuch force that the foil bag bursts open. It must be taken intoconsideration that often only a partial emptying of the foil bag leadsto undesirable changes to the mixing ratio, and thus to a worsening ofthe properties of the finished mixture. It is also disadvantageous thatthis arrangement is only suitable for mixing, but not for applying thepaste.

DE 93 03 268 U1 describes a multiple component mixing capsule with anapplication device for a mixed mass, particularly for dentalapplications. This mixing capsule contains an activation pin located inthe interior of the capsule, wherein this pin is fastened with mountingsin the interior of the capsule body against the pressing direction, aswell as a fluid compartment arranged in the interior of a stamp, whereinthe compartment is sealed against the activation pin with a destructiblemembrane. The activation pin is fit flush in the empty container in theinterior of the die and seals it during the pressing operation. Duringpressing in the longitudinal direction, fluid reaches the mixing chamberthrough thin capillaries, which rest in the interior of the activationpin. It is also stated that during the mixing process in a vibratoryagitator and during the ejection of the mass through the ejection sleevealways a small, not exactly reproducible fluid residue remains in thecapillary. This impairs the quality of the mixing result.

A comparable mixing capsule is described in patent application WO00/30953. The disadvantage in this mixing capsule is that, uponactivation of the capsule, the ball can lead to the development ofsignificant noise. Additionally, the application of force caused by themixing body can lead to a separation of the separating foil, which canlead to an undesirable contamination of the material that is to bemixed.

Making an improved mixing capsule that avoids the above-mentionedproblems without impairing the desired mixing result can be regarded asa primary objective of the invention.

Furthermore, it is the task of the invention to make a device availablethat permits the mixing and application of multiple component materialsin a simple manner.

This task is resolved with a mixing capsule and a method as described inthe claims.

The terms “comprise” or “contain” in the sense of the inventionintroduce a list of features that is not complete. The term “a/one”should be interpreted as an undetermined quantity in the sense of “atleast one”.

The mixing capsule of the invention exhibits, among other things, thefollowing advantages:

The movable body contained in the mixing capsule serves on one hand foractivation of the capsule while destroying the separating device, and,on the other hand, it supports the mixing process.

The fact that the body can change its outward shape during the mixingprocess continuously decreases noise during the mixing process.

Beyond that, the application of the mixed mass by the mixing body is notimpaired, which is beneficial particularly in the application of highlyviscous material.

Associated with this is possibly also a reduction of the force that mustbe generated to apply the mass by sliding the piston.

Through the destruction of the outward shape of the body, additionallythe risk of separating the separating device from the piston during themixing process and of contaminating the mass to be mixed with theseparated parts and thus impair the application process is reduced.

A change in the outward shape in the sense of the invention meansplastic deformation, surface enlargement, destruction of the outwardappearance, pulverization of the body material, integration and/orinclusion of the material that surrounds the body and/or of which thebody basically consists in the substance that is to be mixed.

Since the body in the original state is located in the main chamber,activation preferably occurs automatically at the beginning of themixing process, contrary to the activation types from the state of theart, which are performed manually.

Since the secondary chamber is separated from the main chamber by theseparating device to be penetrated by the body, a portion of the mixingchamber is formed on its own during the subsequent mixing process. Thisway it is ensured that the second component contained in the secondarychamber completely blends with the created mixture.

Additionally, the contamination of main and secondary chambers leads toa beneficial enlargement of the mixing space that is available.

Furthermore, the low quantity and simple design of the components of themixing capsule are advantageous.

If necessary, several freely movable bodies, which change their outwardshape during the mixing process, are located in the mixing capsule.

Preferably, the movable body has a ball shape. The diameter of the ballis preferably in the range of 4 to 10 mm, particularly preferred is therange from 5 to 8 mm. Any other shape of the body however is alsoconceivable, for example a design in the shape of an ellipsoid, or aconfiguration with corners and edges, possibly in the shape of a cube.Such a design may destroy the separating layer more easily and maypermit a smaller mass and/or size of the body.

The weight of the movable body is adjusted to the characteristics of theseparating device in such a way that the separating device is notdamaged by the movable body during conventional transport and regularhandling processes. It is only beyond acceleration values that generallyoccur in capsule mixing devices of, for example, 100 to 500 g (1 g=9.81ms⁻²), preferably 200 to 400 g, that the separating device can bepenetrated.

Ball materials that can be used have a density in the range of 1.5 to9.0 g/cm³, preferably in the range of 2.0 to 6.0 g/cm³. The mass of thebody is generally in the range of 0.1 to 2.0 g, preferably in the rangeof 0.2 to 1.0 g.

For the body in the mixing capsule in particular materials that do notnegatively influence the properties of the mixed mass are suited. Suchmaterials are preferably of inorganic nature, possibly of ceramic natureand comprise, e.g., glass, silicon oxide, aluminum oxide, or zirconiumoxide.

Contamination of the mixed mass by material from the body can also beavoided by producing the body out of the same material, if necessarycomprising it, that is used as the first component in powder and/orgranular form in the main chamber of the capsule. The body is preferablyproduced in a pressing operation from the material of the firstcomponent.

It is also conceivable that the main chamber apart from the bodycontains no additional component, and that all material of the firstcomponent that is to be mixed already exists as a body in the pressedstate.

Such an embodiment is particularly beneficial if it is to be avoidedthat the impulse of the body during the mixing process be dampened bythe powdery material of the first component contained in the mainchamber. This enables possibly a reduction in the weight of the body,which is required to penetrate the partition wall.

Additionally, this embodiment enables a reduction in the size of themixing capsule, since during the mixing operation the dissolving bodybecomes a part of the material that is to be mixed and thus does notlimit the volume required for the mixing process.

The shape of the secondary chamber may have the shape of a hemispherewith a somewhat larger radius compared to the body. Any other design,for example a cylindrical shape, is also conceivable.

The overall volume of the mixing capsule available for the mixingprocess is generally in the range of 0.5 to 5 ml, particularly 1 to 3ml. Preferably, the volume of the secondary chamber is less than thevolume of the main chamber. The volume of the secondary chamber isgenerally 0.05 to 0.5 ml, preferably 0.1 to 0.3 ml.

The mixing capsule according to the invention also does not necessarilyrequire the existence of channel-shaped indentations, which for examplecan be incorporated in the secondary chamber in the form of groovesand/or into the front wall of the main chamber in the shape of troughs,in order to guarantee application of particularly highly viscoussubstances from the mixing capsule.

In a particular embodiment, the separating device has at least onerupture joint, which independently of the properties of the peripheralarea of the piston contributes to a focused and safe opening of thesecondary chamber on the transition to the secondary chamber. Priordamage of the separating device and/or the preparation of a targetbreakage area can occur for example through radiation, such as laserradiation, mechanically through slitting or cutting with a knife orthermally through melting or perforation with a heated blade.

Preparation occurs preferably only on the possibly existing syntheticpart of the separating device, i.e., on the substrate available on oneor both sides of a metal layer or SiO_(x)-containing layer. This way thecloseness of the possibly existing metal or SiO_(x)-containing layer ismaintained.

The preparation method is a matter of choice here, but preferably takeson a form that avoids tearing the separating device or parts thereofafter or during penetration of the separating device by the body. Apreparation of the separating device in the form of two or more linesintersecting in the axis of symmetry of the capsule has provenfavorable.

Useful is also a star-shaped preparation with branching sections. Such apreparation facilitates the mixing process since wedge-shaped foil partsof the separating device in the area of the wall of the secondarychamber have a shorter side length, allowing the foil components to befolded over more easily during the mixing operation.

A preparation in which a foil part has the outline of a bowling pin isalso beneficial, wherein the pinhead has a circular design and islocated in its center on the longitudinal axis of the cartridge. Thispreparation facilitates the largely complete opening of the separatingdevice and thus access to the secondary chamber as well.

Suitable preparations of the separating device are shown schematicallyin FIGS. 3 and 4.

In this case, the separating layer only bursts in a defined location.This avoids that the separating layer or parts thereof reach the mixtureand prevent the ejection process.

Another benefit of a target breakage area generated this way consists ofthe fact that also relatively thick foils, also multi-layer foils in therange of 50 to 80 μm, preferably 60 to 70 μm, can be penetrated withlittle force (smaller mass of the body).

The separating device preferably sticks to a ring surface of the pistonlimiting the secondary chamber. The transition between the ring surfaceand the interior wall of the secondary chamber may have a sharp-edgedarea.

This sharp-edged area extends preferably across a section of theperiphery, preferably basically from 60° to 120°, particularly preferredfrom 70° to 90°. The transition between the ring surface and theinterior wall of the secondary chamber is preferably rounded off in theremaining area. This embodiment avoids that the foil is torn offcompletely.

The separation device preferably exists in the form of a single- ormulti-layer foil, particularly preferred in the form of a sandwich foilor also a sealant foil. The foil preferably comprises at least one metallayer, such as an aluminum layer and/or gold layer, and at least one,possible two, three or more, plastic layers. A three-layer foil,comprising a plastic outer layer, at least one barrier layer, preferablymade of resin, and a sealant layer, has proven beneficial, wherein thesealant layer can also be a synthetic foil or a sealant paint.

Furthermore, the separating device can contain plated or other resinbarrier layers, plasma polymerized layers such as hydrocarbon containinglayers, or ceramic barrier layers such as SiO_(x) layers instead of orin addition to the metal foil.

The separating device is fastened to the circular-shaped end face of thepiston, for example, through heat sealing, gluing, ultrasound welding,or high frequency welding.

Layers comprising PET, PP, PE, PTFE, PVC and/or PA are suitable, forexample, for the outer layer, layers comprising Al, SiO_(x), PVDC and/orEVOH for the blocking layer, layers comprising HDPE, LDPE and/or PP forthe sealant layer. A PET-Al-LDPE or PA-Al-LDPE coating has provenuseful.

The layer thickness of the individual foils (outer layer, blockinglayer, sealant layer) is in the range of 5 to 60 μm, preferably from 8to 50 μm.

The separating device can furthermore be designed to hold a thirdcomponent, for example in the form of a foil cushion.

Beneficial materials for the piston of the mixing capsule comprisemetals such as anodized aluminum, titanium, and iron-containingmaterials such as steel sheets and synthetics. In order to reduce thepermeability of synthetic-containing pistons towards liquids and gases,such a piston may contain plated materials or synthetics vaporized orcoated with other materials that have a blocking layer effect.Synthetics that are possible include PE, PP, PET, PTFE, PVC, andpolyamides.

Furthermore, combinations of the above-mentioned materials, such as ametal insert, preferably made of aluminum or steel, are feasible,surrounded on the inside and outside with the synthetic. Such parts canbe produced in an injection molding procedure. Production throughthermo-forming and/or deep-drawing of e.g. aluminum composite foils orresin-coated steel metal sheets is also conceivable.

The piston can be manufactured in a 2-component injection moldingprocedure. For this, initially an inlay is produced, which issubsequently surrounded with, e.g., PE.

Application of the mixed mass from the mixing capsule generally occursthrough the use of a suitable application device. Such a device usuallycontains a die, which moves the piston of the mixing capsule in thedirection of the application orifice via lever action.

If a nearly complete emptying of the mixing capsule is to be ensured,dead space must be avoided. Such dead space can present a problemparticularly with highly viscous masses, and have a disadvantageouseffect when the overall volume of the mixed mass is small compared tothe volume of the dead space.

If the dead space is to be kept as small as possible, it is beneficialwhen no additional indentations (for example, in the shape of a trough),are embedded in the pistons and/or the front wall of the main chamber.

The piston is preferably designed such that it can be subjected todeformation during the application process, in particular to plasticdeformation. The deformation preferably occurs in such a way that thepiston adapts to the shape exhibited by the mixing capsule at the end onwhich the ejection sleeve is located.

This can be accomplished by ensuring that the piston, which contains atleast one secondary chamber, consists of a ductile material, orcomprises such a material.

A design in such a geometric shape that facilitates such deformation isalso useful.

It has also proven favorable to use a design of the piston in the formof a tubular piston that is open on two sides, with a first and a secondrecess, wherein the first recess together with the separating deviceforms the secondary chamber.

Such a form can be attained, for example, by pressing in the bottomsurface of a cup consisting of a deformable material. Pressingpreferably occurs with a die, in particular a hemispherical die.

It is also conceivable to produce such a piston through molding ordeep-drawing and/or thermo-forming of a ductile material.

To ensure that the piston is better sealed against the capsule wall, thepiston preferably contains one or more sealing lips.

An additional sealing effect can be accomplished by a design th atpermits an expansion of the collapsing piston during the applicationprocess, associated with a pressing against the capsule wall.

If necessary, the escape of volatile substances, which are located inparticular in the secondary chamber of the mixing capsule, can beprevented through the application of a sealant foil onto the bottom-sideopening of the mixing capsule into which the piston is introduced.

The combination of ductile pistons and mixing bodies whose outward shapeis destroyed during the mixing process and/or which is incorporatedduring the mixing process into the mass that is to be mixed isparticularly beneficial when a nearly complete ejection of the mixedmass is to be ensured.

In order to ensure complete ejection of the mixture from the mixingcapsule, it may also be beneficial to attach a molded part to the outerside of the piston bottom. Such a molded part can take on the shape of athickening of the piston bottom or a distance piece, preferably incylindrical shape. Since for the ejection of the mixture an applicationdevice is required, which has a movable piston rod or a die with adefined length that is standardized for the market, it may becomenecessary to extend the axial length of the die via the molded part.This way, it can be assured that the ductile piston can be shifted allthe way to the ejection sleeve. Furthermore it is beneficial that therisk for the piston rod or the die of the application device to becomestuck during deformation of the piston of the mixing capsule is thusreduced.

The components contained in the main chamber, the secondary chamberand/or possibly in the separating device comprise both fluids and solidmatters, preferably in powder form. However paste-like basic substancesare also possible.

The solid matter comprises inert fillers, such as finely ground quartz,SiO_(x)-containing substances, glass, and reactive fillers of all kinds,wherein the solid matter may exist in a surface-modified way.

The fluids comprise, in particular, matrix-forming, polymerizablesubstances, for example polyacids, comprising acrylic acid, methacrylicacid, and maleic acid derivatives as well as copolymers thereof.

The mixing capsule is preferably suited for storing, mixing and applyingglass ionomer cements.

The ejection sleeve on the mixing capsule preferably attaches in acoaxial, possibly also in an eccentric manner to the main chamber.

The ejection sleeve furthermore has a closable design. Feasibleembodiments are described, for example, in EP 0 157 121 A, where theejection sleeve is seated in a swiveling manner so that depending on theposition of the ejection sleeve that spout is closed or opened. Alsofeasible is the use of a blowpipe displacement cap for closing theejection sleeve.

The mixing capsule may contain coding. Suitable codings are, forexample, color markings, such as in the form of color rings, labels,imprints or electronically legible codings (bar codes). It is alsofeasible that several codings are applied. The coding can containinformation about the mixing time, the material, the manufacturer and/orthe expiration date. Coding can also occur through the coloration of amixing capsule component, preferably the sleeve.

A coding of the mixing capsule or the substances found therein through acolored design of the ejection sleeve is particularly advantageous whenphoto-sensitive substances are to be stored in the mixing capsule. Inorder to protect them from incident light, it is often necessary tocolor the piston and/or the cartridge black. If substances of differingcolors are to be stored in the cartridge, identification of thesesubstances can no longer occur through the color of the now black pistonand/or cartridge.

The object of the invention is also a method for mixing and applyingmixtures from mixing capsules, including the following steps:

-   -   a) making a mixing capsule available with at least two chambers        in which components of the mixture are stored separately from        each other, separated by a separating device, comprising a        cartridge, a piston that is arranged displaceably in the        cartridge, an ejection sleeve and at least one freely movable        body that can penetrate the separating device,    -   b) inserting the mixing capsule in a mixing device with a        capsule holder,    -   c) accelerating the mixing capsule preferably through rapid        translatory and/or rotatory movements, wherein the at least two        chambers that are separated by a separating device are opened        while forming a mixing chamber,    -   d) removing the mixing capsule from the mixing device, and    -   e) sliding the piston while utilizing an application device with        a piston rod, wherein the mixture created in c) is introduced        into or removed from a surface, especially dental hard tissue or        a tooth cavity, via the ejection sleeve of the mixing capsule.

A conventional application device comprises a mounting for inserting themixing capsule and a sliding piston rod that is dimensioned such that itcan move the piston of the mixing capsule in the direction of theejection opening.

Preferred embodiments of the mixing capsule are explained in thefollowing based on the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a longitudinal section through a mixing capsule in theinitial state;

FIG. 2 shows the same capsule at the end of the ejection process;

FIG. 3 shows possible preparations of the separating device in top view;and

FIG. 4 shows a top view of a preparation of the separating device.

DETAILED DESCRIPTION OF THE DRAWINGS

According to FIG. 1, the mixing capsule comprises a cylindricalcartridge 10, which on its front end is closed by a front wall 11 and onits rear end by a piston 12. On the front wall 11 an arched ejectionsleeve 14 is molded on coaxially to the cartridge axis 13. The ejectionsleeve 14 can be designed in a locking manner, for example with adisplacement plug.

The piston 12 is equipped with an indentation that is coaxial to thecartridge axis 13, with this indentation being closed by a separatingdevice 16 that is fastened to the ring-shaped front end face 15 of thepiston 12. The separating device 16 separates the secondary chamber 17formed by the indentation from the remaining interior of the cartridge,which is called the main chamber 18 here. The piston 12 possessesanother coaxial indentation on the side opposite the secondary chamber,wherein this indentation is adjusted to the shape of the secondarychamber.

In the original and/or storage state, the main chamber 18 may possiblycontain a first, for example, powdery and/or granular component and thesecondary chamber 17 a second, for example, liquid component of themixture that is to be prepared.

The mixing capsule furthermore contains a freely movable, possiblyball-shaped body 19, which, in the original and/or storage state of thecapsule, is located in the main chamber 18 and whose radius ispreferably somewhat smaller than the radius of the indentation formingthe secondary chamber 17. The body 19 and the secondary chamber 17 cantake on other shapes deviating from a ball or hemispherical shape.Freely movable means that the body can basically move in all directionsand is not impaired by any guiding rails in its movement.

The transition between the indentation forming the secondary chamber 17and the preferably ring-shaped end face 15 of the piston 12 ispreferably rounded off, however can also have sharp edges through anangled area. The sharp edges can also be generated through a toothedsection. The rounded-off area prevents the separating device fromrupturing in this end face interior edge area during the mixing process.

When the edge of the secondary chamber 17 is rounded all the way, theseparating device 16 can be ruptured by overextending it through theimpact of the body 19 at the beginning of the mixing process preferablyin the rupture joint.

For applications, the mixing capsule, which is supplied by themanufacturer in the state depicted in FIG. 1, is generally inserted intoa conventional capsule mixing device, where it is brought tooscillation, for example along the cartridge axis 13. Apart from purelytranslatory movements of the capsule, rotatory movements are possible,if necessary in combination with translatory movements. The body 19 thenmeets with the separating device 16 and penetrates it. This causes themain chamber 18 and the secondary chamber 17 to be combined to a jointmixing chamber. In this mixing chamber, the components are blendedduring the continued mixing process. During the mixing operation thebody 19 disintegrates and is embedded, preferably worked, into the massthat is being mixed.

For ejection of the finished mixture, the piston 12 is shifted forwardin a conventional application instrument with a die 20 until it hasreached the position shown in FIG. 2, dependent upon the materialproperties of the piston, and preferably no longer has a secondarychamber.

The deformation preferably occurs with the simultaneous reduction involume of the secondary chamber only when the ring surface 15 of thepiston 12 has come to rest against the front wall of the cartridge. Thiscan be achieved for example by ensuring that the frictional forcebetween the piston and the interior cartridge wall is lower than theforce that must be applied to deform the piston.

FIGS. 3 and 4 show a top view of possible preparations of the separatingdevice 16, which enable the mixing capsule to be activated in a simpleand largely complete manner, without embedding components of theseparating device in the mixed mass during the mixing operation.Preparation preferably occurs by previously damaging the foil used asthe separating device, for example through radiation.

The mixing capsule is generally used together with another device.Device, in the sense of the invention, should be interpreted on one handas an apparatus that is used to activate the mixing capsule, preferablyan apparatus that can cause the mixing capsule to perform translatoryand/or rotatory movements, and on the other hand as an apparatus thatfacilitates the application of the mixed mass from the mixing capsule,preferable a device comprising a die and/or a sliding piston rod.

1. A mixing capsule, comprising: a first end; an ejection sleeve influid communication with said first end; a second end opposite saidfirst end and defined by a piston; a separating device disposed betweensaid first and second end; a main chamber disposed between said firstend and said separating device; a secondary chamber disposed betweensaid second end and said separating device; at least one body providedin said main chamber; a first component provided in said main chamber;and a second component provided in said second chamber, wherein saidpiston comprises a deformable material; wherein said at least one bodycan penetrate said separating device; and wherein said at least one bodyhas an outward shape which changes during use of the mixing capsule. 2.A mixing capsule according to claim 1, wherein said outward shape ofsaid at least one body is selected from the group consisting ofspherical, ellipsoid and angular.
 3. A mixing capsule according to claim1, wherein said first component comprises said at least one body.
 4. Amixing capsule according to claim 1, wherein said separating device issubjected to a preparation process prior to use to form at least onerupture joint.
 5. A mixing capsule according to claim 4, wherein saidrupture joint forms a shape selected from the group consisting ofstar-shaped, branched in a star-shaped pattern, and cone-shaped.
 6. Amixing capsule according to claim 1, wherein a frictional force betweensaid piston and an exterior wall defining said main chamber is less thana deforming force required to deform said piston.
 7. A mixing capsuleaccording to claim 1, wherein said deformable material of said pistoncomprises at least one of metals or synthetics.
 8. A mixing capsuleaccording to claim 1, wherein said piston is tubular and comprisescoaxial indentations on two sides.
 9. A mixing capsule according toclaim 1, wherein said separating device comprises at least one itemselected from the group consisting of a metal-containing foil, ahydrocarbon-containing layer, and a ceramic barrier layer.
 10. A mixingcapsule according to claim 9, wherein said ceramic barrier layercomprises SiO_(X).
 11. A method of mixing a dental material, comprising:providing components of a dental material in a mixing capsule accordingto claim 1; and accelerating said mixing capsule.
 12. A method of usinga mixing capsule, comprising: inserting the mixing capsule into acapsule holder of a mixing device; accelerating the mixing capsulethrough at least one of translatory movement and rotatory movement;removing the mixing capsule from said mixing device; and releasing atleast one content of said mixing capsule, wherein said mixing capsulecomprises a cartridge separated into at least two chambers by aseparating device, at least one freely movable body capable ofpenetrating said separating device, an ejection sleeve in fluidcommunication with said cartridge, and a piston displaceably disposed insaid cartridge; and wherein said at least one content of said mixingcapsule is released by displacing said piston to force said at least onecontent out of said cartridge through said ejection sleeve.
 13. A methodof using a mixing capsule according to claim 12, wherein a first dentalmaterial component is disposed in a first chamber of said mixingcapsule, and a second dental material component is disposed in a secondchamber of said mixing capsule.
 14. A method of using a mixing capsuleaccording to claim 13, wherein said first dental material componentcomprises said at least one freely movable body.
 15. A method of using amixing capsule according to claim 12, wherein said piston is deformable.16. A method of using a mixing capsule according to claim 15, wherein africtional force between said piston and said cartridge is less than aforce required to deform said deformable piston.
 17. A method of makinga mixing capsule for a dental material, comprising: forming a mainchamber and a secondary chamber separated by a separating device;providing a first component in said main chamber; providing a secondcomponent in said secondary chamber; providing at least one body in saidmain chamber, wherein a portion of said second chamber not defined bysaid separating device comprises a deformable piston; and wherein saidat least one body is configured to penetrate said separating device. 18.A method of using a mixing capsule, comprising: providing a bodycomprising a first component of a dental material in a main chamber of amixing capsule; providing a second component of a dental material in asecondary chamber of said mixing capsule, which secondary chamber isdefined in part by a deformable piston; providing a separating devicebetween said main chamber and said secondary chamber, said separatingdevice defining portions of the secondary chamber not defined by thedeformable piston; placing said mixing capsule in a mixing device; andaccelerating said mixing capsule with consequent movement of said bodyto penetrate said separating device.